    :tree '("weka.classifiers.misc.HyperPipes"
            "weka.classifiers.trees.RandomTree"
            "weka.classifiers.trees.RandomForest"
-           ;"weka.classifiers.trees.NBTree"
+                                        ;"weka.classifiers.trees.NBTree"
            "weka.classifiers.trees.REPTree")
    :zeror '("weka.classifiers.rules.ZeroR")
    :svm '("weka.classifiers.functions.LibSVM")

  and evaluate body **exprs**.

  Example:
```
(let-classifier
    (langid-baseline [inst]
       (let [attrib (weka/attribute-by-name inst \"langid-1-id\")
             val (.stringValue inst attrib)

                                (.setValueSparse inst idx weight)))
                         doall)
                    (if add-class?
                      (.setValueSparse inst (.index label-attrib) (label-map name)))
                    (if def-array
                      (.replaceMissingValues inst def-array))
                    (.add insts inst)
